Production process of multifunctional composite copper foil and composite copper foil and application thereof

Abstract

The invention relates to the technical field of composite copper foils, in particular to a production process of a multifunctional composite copper foil, the composite copper foil and application of the composite copper foil. The invention provides a production process of a multifunctional composite copper foil. The production process comprises the following steps: S1, baking a carrier layer; s2, performing surface treatment through plasma treatment; s3, coating a film on the baked carrier layer through magnetron sputtering to form a bottom layer; s4, evaporating a vacuum evaporation layer on the base layer through vacuum evaporation; s5, plating a copper layer on the vacuum evaporation layer through water electroplating; and S6, slitting the sample. According to the production process, by optimizing the baking conditions, the sputtering technology and the evaporation parameters and introducing the plasma surface treatment technology, the binding force of the copper film and the base material is improved, the pinhole rate is reduced, the production efficiency and the coating uniformity are remarkably improved, and the product quality is improved. The problems that in the existing composite copper foil production process, the binding force between a copper film and a base material is poor, the pinhole rate of the copper film is high, the deposition speed is low, and the coating uniformity is poor are solved.

Description

Technical Field

[0001] The invention relates to the technical field of composite copper foil, and in particular to a production process of a multifunctional composite copper foil and the composite copper foil and application thereof. Background Art

[0002] Composite copper foil refers to a thin film material with a polymer material as the middle layer and metal copper as the coating on both sides. At present, the main materials of the middle layer of composite copper foil include PET, PP, and PI. Different polymer materials have different properties. From the production process of composite copper foil, the production process of composite copper foil is greatly shortened, and the commonly used economic process for composite copper foil is water electroplating. However, due to the high crystallinity and low intermolecular polarity of polymer materials, it will affect the adhesion between the coating and the substrate, and most polymer materials are non-conductive insulators. Therefore, it is necessary to deposit a conductive metal film on the surface of the polymer material before electroplating.

[0003] This process mostly uses the vacuum magnetron sputtering process, with extremely high purity copper as the target material, and vacuum nano-scale coating is performed on the carrier layer. The copper target material is bombarded once or multiple times to make it deposited on the surface of the PET, PP, and PI carrier layers, and sputtered to form a metal copper film. However, the magnetron sputtering process also often faces problems such as poor bonding between the copper film and the substrate, and high pinhole rate of the copper film. In addition, due to the slow deposition speed of conventional magnetron sputtering technology, a production capacity bottleneck is caused, and the uniformity of the coating is poor, which will affect the effect of water electroplating. Therefore, a vacuum evaporation process is added on the basis of magnetron sputtering to improve the uniformity of the base layer and improve product quality. Summary of the invention

[0004] The present application provides a production process of a multifunctional composite copper foil, its composite copper foil and application. The production process described in the present application includes the steps of baking a carrier layer, surface treatment of the carrier layer, magnetron sputtering coating, vacuum evaporation layer, water electroplating copper layer and slitting. By optimizing the baking conditions, sputtering technology and evaporation parameters, and introducing plasma surface treatment technology, not only the bonding force between the copper film and the substrate is improved and the pinhole rate is reduced, but also the production efficiency and the uniformity of the coating are significantly improved, and the technical problems existing in the existing composite copper foil production process, such as poor bonding force between the copper film and the substrate, high pinhole rate of the copper film, slow deposition speed and poor coating uniformity, are solved.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] In a first aspect, the present application provides a production process of a multifunctional composite copper foil, comprising the following steps:

[0007] S1. Baking the carrier layer;

[0008] S2. Perform surface treatment;

[0009] S3. coating a bottom layer on the baked carrier layer by magnetron sputtering;

[0010] S4. Vacuum evaporation is performed on the bottom layer to form a vacuum-deposited layer;

[0011] S5. Plating a copper layer on the vacuum evaporated layer by water electroplating;

[0012] S6. Cutting is performed.

[0013] Preferably, in step S1, the baking temperature is 40-60°C, and the baking time is 12-18 hours.

[0014] Preferably, in step S2, the surface of the film is treated using plasma technology, and the mixing ratio of argon and oxygen is 98:2. Plasma treatment can increase the roughness of the film surface and improve the bonding strength between layers.

[0015] Preferably, in step S3, the vacuum degree of magnetron sputtering deposition is 5×10 -4 -1×10 -3 Pa, planar magnetron sputtering target and cylindrical magnetron sputtering target are used for sputtering coating, and copper is used as the sputtering target material.

[0016] Preferably, in step S3, a copper coating less than 100 nm is coated on the carrier layer, and a copper target is sputtered using high-purity argon as a sputtering gas. The copper target is bombarded by argon ions, and the sputtered copper atoms are deposited on the surface of the carrier layer under the action of an electromagnetic field. Finally, a copper film is deposited on the surface of the carrier layer to form a base layer.

[0017] Preferably, in step S1 , the material of the carrier layer includes but is not limited to: any one or more of PET (polyethylene terephthalate), PP (polypropylene), and PI (polyimide).

[0018] Preferably, in step S4, the vacuum evaporation temperature is 950° C. to 1050° C., the coating speed is 30 m / min, and the coating thickness is 100 nm.

[0019] Preferably, in step S5, the water electroplating is performed by immersing the film material obtained in step S4 in a copper sulfate solution for electroplating at 30-45°C, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 80-120 g / L, the mass concentration of copper sulfate is 120-140 g / L, and the mass concentration of chloride ions is 20-50 ppm.

[0020] Preferably, in step S5, after the water electroplating is completed, passivation is performed; the operating temperature of the passivation is 20-30°C.

[0021] In a second aspect, the present application provides a multifunctional composite copper foil, which is a composite copper foil prepared by the above production method.

[0022] In a third aspect, the present application provides an application of a multifunctional composite copper foil, wherein the multifunctional composite copper foil is applied to prepare a battery.

[0023] The beneficial effects of this application are:

[0024] The production process described in the present application includes the steps of baking a carrier layer, surface treatment of the carrier layer, magnetron sputtering coating, vacuum evaporation layer, water electroplating copper layer and slitting. By optimizing the baking conditions, sputtering technology and evaporation parameters, and introducing plasma surface treatment technology, not only the bonding strength between the copper film and the substrate is improved and the pinhole rate is reduced, but also the production efficiency and the uniformity of the coating are significantly improved, and the technical problems existing in the existing composite copper foil production process, such as poor bonding strength between the copper film and the substrate, high pinhole rate of the copper film, slow deposition speed and poor coating uniformity, are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 A flow chart of a production process of a multifunctional composite copper foil described in the present application. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0028] As used herein, "and / or" includes the term of any and all combinations of one or more associated listed items. The terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It is further understood that "including", when used in this specification, specifies the stated features, integers, steps, operations, elements and / or compositions, but does not exclude the existence or addition of one or more other features, integers, steps, operations, elements, compositions and / or combinations thereof.

[0029] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. It is further understood that terms, such as defined in commonly used dictionaries, are interpreted in accordance with their meanings in the context of the relevant art and are not in an idealized or overly formal sense unless explicitly so defined herein.

[0030] The exemplary invention described herein may appropriately lack any one or more element limitations that are not specifically disclosed herein. Therefore, the terms "comprise", "include", "contain", etc. should be understood broadly and non-restrictively. In addition, the terminology used herein is used as a description, not a limitation, and it is unintentional to use these terminology expressions that do not include any equivalent characteristics, but only describe some of their characteristics, but various modifications are possible within the scope of the present invention according to the rights. Therefore, although the present invention has been specifically disclosed by preferred embodiments and optional features, the modifications disclosed herein to embody the changes of the present invention may be recorded by those skilled in the art, and such modifications and changes will be considered to be within the scope of the present invention.

[0031] The present application discloses a production process of a multifunctional composite copper foil. The prepared multifunctional composite copper foil can be directly used in a positive electrode current collector or a negative electrode current collector and applied to the preparation of batteries. The production process can speed up production efficiency and solve the problems of poor density, breakdown, PP bonding strength and efficiency of magnetron sputtering in traditional production processes.

[0032] A production process of a multifunctional composite copper foil comprises the following steps:

[0033] S1. Use a blast drying oven to bake the carrier layer, keep the temperature at 40-60°C, and bake for 12-18 hours; by baking the carrier layer, volatilize the water vapor and oil vapor on the surface of the carrier layer as much as possible. The polymer base film is used as the carrier layer, and the polymer base film includes but is not limited to: PET (polyethylene terephthalate), PP (polypropylene), PI (polyimide).

[0034] S2. Use plasma technology to treat the surface of the film. The plasma gas is composed of a mixture of argon and oxygen. The mixed volume ratio of argon and oxygen is 98:2. The mixed gas of argon and oxygen is used to generate plasma under high voltage. The high-energy particles and free radicals in the plasma react with the surface of the film to increase the surface roughness, thereby improving the bonding force between the film layers. In addition, plasma treatment can change the chemical properties of the film surface, increase the surface tension, and help subsequent processing and application.

[0035] S3. Magnetron sputtering coating base, the vacuum degree of magnetron sputtering deposition is 5×10-4 -4 ×10 -3Pa, using planar magnetron sputtering target (6*127*1700mm) and cylindrical magnetron sputtering target (100*80*1700mm) for sputtering coating, using high-purity copper (99.99%) as sputtering target material. First, a copper coating less than 100nm is coated on the carrier layer, and then high-purity argon is used as sputtering gas to sputter the copper target. The copper target is bombarded by argon ions, and the sputtered copper atoms are deposited on the surface of the carrier layer under the action of the electromagnetic field. Finally, a copper film of about 100nm is deposited on the surface of the carrier layer, and the coating speed is 20m / min~40m / min.

[0036] S4. Evaporation coating

[0037] The main purpose of this step is to lay the foundation for subsequent coating, increase conductivity, and facilitate subsequent water electroplating to better control the film thickness. Evaporation coating uses high vacuum evaporation coating equipment for pre-coating, and uses high-purity copper wire (purity is 99.9%) as raw material for high-temperature evaporation coating. The evaporation boat temperature is 950℃~1050℃, the coating speed is 30m / min, and the coating thickness is 100nm. After high-temperature evaporation, 100nm thick copper is finally deposited on the S2 film material.

[0038] S5. Thicken the surface metal layer by water electroplating, and further thicken the copper layer by copper sulfate electroplating to a total thickness of about 1.0 μm, that is, at 30-45°C, immerse the film material obtained in step S3 in a copper sulfate solution for electroplating, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 80-120 g / L, the mass concentration of copper sulfate is 120-140 g / L, and the mass concentration of chloride ions is 20-50 ppm. After the water electroplating is completed, passivation is performed; passivation: passivation agents are used, including but not limited to organic passivation using citric acid, phytic acid, epoxy resin, acrylic acid, diaminotriazole, etc., and inorganic passivation includes molybdates, tungstates, silicates, rare earth salts, rare earth oxides, titanium salts, zirconium salts, etc., to form a passivation film on the surface of the copper foil. A dense oxide film is produced on the surface of the product to further increase the protection capability, and the operating temperature is 20-30°C.

[0039] S6. Cutting.

[0040] The samples were slitting and rewinding under a tension of 110-130N.

[0041] Specifically, in step S1, the carrier layer is baked, which is a pretreatment step to create better surface conditions for subsequent magnetron sputtering and coating processes. The baking process uses heat treatment to volatilize water vapor and oil vapor on the surface of the carrier layer, thereby cleaning the surface and improving the adhesion and coating quality of subsequent processes.

[0042] Specifically, in step S1, the baking process is carried out at a temperature range of 40-60°C for 12-18 hours. The selection of this temperature and time is based on a deep understanding of the characteristics of the carrier layer materials such as polymer materials such as PET (polyethylene terephthalate), PP (polypropylene), and PI (polyimide). These materials may deform or degrade at high temperatures, so a moderate temperature range is selected to effectively remove surface contaminants without damaging the physical and chemical properties of the materials.

[0043] The principle of baking is based on thermodynamics. By increasing the temperature and increasing the thermal motion of molecules, the water molecules and oil molecules adsorbed on the surface of the carrier layer can obtain enough energy to detach from the surface and evaporate. This process not only removes pollutants that may affect the quality of the coating, but also helps to reduce the stress inside the material, providing a more uniform and smooth surface for the subsequent magnetron sputtering process.

[0044] Through the S1 step, the problems of uneven coating and insufficient adhesion caused by surface contaminants are solved. Secondly, by reducing the internal stress of the material, the stability of the material is improved, which helps to maintain the integrity of the film layer in subsequent processes. In addition, baking also helps to improve the interface bonding strength between the carrier layer and the subsequent coating, which is crucial to the mechanical and electrical properties of the final product.

[0045] Through step S2, in the surface treatment link, plasma technology is used to treat the surface of the film. Plasma is a gas containing a large number of active particles (such as ions, free radicals and excited molecules) with high chemical reactivity. By mixing argon and oxygen in a certain ratio (for example, 98:2), the generated plasma can effectively clean and activate the surface of the copper foil, increase the surface roughness, and thus improve the bonding force between the copper foil and other materials (such as electrode materials). This treatment not only helps to improve the electrochemical properties of the copper foil, but also enhances its mechanical stability in applications such as batteries, improves the surface activity and bonding force of the composite copper foil, and enhances the bonding performance of the copper foil and other materials through plasma treatment, which is beneficial to improve the electrochemical performance of applications such as batteries;

[0046] Specifically, in step S3, a base layer is coated on the baked carrier layer by magnetron sputtering. This step adopts magnetron sputtering technology, which is a physical vapor deposition (PVD) method. Its principle is to use high-purity argon as sputtering gas, bombard the copper target with argon ions, so that copper atoms are sputtered from the surface of the target, and deposited on the surface of the carrier layer under the action of the electromagnetic field to form a uniform copper film.

[0047] In step S3, a copper coating with a thickness less than 100 nm is first applied on the polymer base film. This thin copper film serves as a base layer, providing a good adhesion foundation for the subsequent vacuum evaporation layer and water electroplating layer. During the magnetron sputtering process, the vacuum degree is controlled at 5×10 -4 to 1×10 -3 Pa. The vacuum degree within this range can ensure the stability of the sputtering process and the uniformity of the copper film. The target material used is high-purity copper with a purity of 99.99%, which ensures the quality and purity of the copper film.

[0048] In step S3, the bonding force between the copper film and the substrate is improved, because magnetron sputtering can achieve the deposition of copper atoms at a lower energy, reducing damage to the substrate, and the effect of the electromagnetic field helps the copper atoms to be closely bonded to the surface of the substrate. Secondly, magnetron sputtering technology effectively reduces the pinhole rate of the copper film, because the high vacuum environment during the sputtering process reduces the interference of gas impurities and improves the density of the film layer. In addition, magnetron sputtering also improves the uniformity of the coating, which is crucial for subsequent vacuum evaporation and water electroplating processes.

[0049] In step S3, by forming a uniform and dense copper film on the carrier layer, a solid foundation is provided for subsequent processes, thereby improving the overall quality and performance of the composite copper foil. Secondly, the production efficiency is improved, because the magnetron sputtering technology can achieve a higher coating speed, and the coating speed in this application is 20m / min to 40m / min, which significantly improves the production capacity. In addition, the application of magnetron sputtering technology also helps to improve the conductivity and mechanical strength of the composite copper foil, which is crucial to its performance in applications such as batteries.

[0050] Specifically, in step S4, a copper film is further deposited on the base layer formed by magnetron sputtering by vacuum evaporation. This step uses vacuum evaporation technology, which is a physical vapor deposition (PVD) method. Its basic principle is to heat a high-purity copper material in a high vacuum environment to an evaporation state, and copper atoms or molecules escape from the evaporation source and condense on the surface of the carrier layer to form a thin film.

[0051] In step S4, high-purity copper wire is used as the evaporation material, and the temperature of the evaporation boat is controlled between 950°C and 1050°C to ensure that the copper material can reach the evaporation conditions. The coating speed is set to 30m / min, and the coating thickness is precisely controlled at 100nm. The precise control of these parameters ensures the uniformity and consistency of the copper film. During the vacuum evaporation process, the carrier layer will not be affected by oxidation or other chemical reactions at high temperatures, thereby ensuring the purity and quality of the copper film.

[0052] In step S4, the conductivity of the copper film is improved because the evaporated copper layer has a higher purity and a lower defect density, thereby providing better conductivity. Secondly, the vacuum evaporation technology effectively solves the problem of coating uniformity by precisely controlling the coating thickness and speed, ensuring the consistency and reliability of the composite copper foil. In addition, since the evaporation process is carried out in a high vacuum environment, the interference of gas impurities is reduced, further improving the density and surface quality of the copper film.

[0053] In step S4, by adding a layer of high-purity copper film on the base layer, the overall conductivity of the composite copper foil is significantly improved, which is crucial for improving the charge and discharge performance in applications such as batteries. Secondly, due to the uniformity and density of the evaporated copper layer, the mechanical strength and durability of the composite copper foil are enhanced, improving its stability and reliability in practical applications. In addition, the application of vacuum evaporation technology also helps to improve production efficiency because the technology can achieve high-speed coating, thereby shortening the production cycle and increasing production capacity.

[0054] Specifically, in step S5, the copper layer is further thickened on the vacuum evaporated layer by an electrochemical method. This step adopts the principle of water electroplating, that is, metal copper is deposited on the conductive substrate by electrolytic reaction, thereby forming a uniform, dense and thick copper plating layer.

[0055] In step S5, first, the vacuum evaporation layer is thickened by copper sulfate electroplating. The electrolyte used contains sulfuric acid, copper sulfate and chloride ions, as well as some conventional organic additives. The organic additives include polyether compounds, sulfur-containing compounds, gelatin, etc. These chemical components work together to ensure the stability of the electroplating process and the uniformity of the copper layer. The operating temperature is controlled at 30-45°C. This temperature range is conducive to improving the electroplating efficiency and the quality of the copper layer.

[0056] In step S5, water electroplating provides an effective method to increase the thickness of the copper layer, thereby improving the conductivity and mechanical strength of the composite copper foil, which is crucial for its performance in applications such as batteries. Secondly, the water electroplating process is highly controllable, and the thickness and performance of the copper layer can be precisely controlled by adjusting parameters such as the concentration of the electrolyte, the electroplating time, and the current density. In addition, the water electroplating technology also helps to improve the corrosion resistance and stability of the composite copper foil, because the electroplated copper layer has better chemical stability and protective properties.

[0057] In step S5, by thickening the copper layer on the vacuum evaporation layer, the conductivity of the composite copper foil is significantly improved, which is of great significance for improving the charge and discharge efficiency and cycle stability of the battery. Secondly, the uniformity and density of the water electroplated copper layer improve the overall performance and reliability of the composite copper foil, making it more durable and stable in practical applications. In addition, the controllability of the water electroplating process also helps to improve production efficiency and reduce costs, because the production speed can be increased and the consumption of raw materials can be reduced by optimizing the electroplating parameters.

[0058] In summary, step S5 successfully thickens the copper layer on the vacuum evaporation layer through water electroplating technology, solves technical problems such as copper layer thickness, conductivity, mechanical strength and corrosion resistance, and brings technical effects such as improving conductivity, mechanical properties, production efficiency and reducing costs. The successful implementation of this step provides a solid foundation for the preparation of high-performance multifunctional composite copper foil and provides strong support for subsequent application development and industrialization.

[0059] Specifically, in step S6, in the slitting process, the surface-treated composite copper foil is precisely slit according to the required size and shape. This step is usually performed under a certain tension to ensure the flatness and dimensional accuracy of the copper foil. For example, the slitting and rewinding mentioned in this application is performed under a tension of 110-130N, which helps to maintain uniform tension of the copper foil, avoid curling or wrinkling, and ensure its consistency and reliability in subsequent applications.

[0060] Through step S6, the dimensional accuracy and consistency of the composite copper foil are ensured, and through precise slitting, the specific requirements of different application scenarios for the copper foil size are met; the mechanical stability of the composite copper foil is improved, and by controlling the tension during the slitting process, the deformation of the copper foil is avoided, thereby enhancing its durability in actual use.

[0061] In summary, through steps S1-S6, a 100nm magnetron sputtering primer layer can be plated on both sides of the carrier layer (PP\PET\PI); a 100nm vacuum evaporated layer can be plated on the primer layer, and a 700-800nm ​​water electroplated copper can be plated on the vacuum evaporated layer.

[0062] Step S6 successfully solves the technical problems of dimensional accuracy and mechanical stability of the composite copper foil through the slitting process, bringing about technical effects in many aspects such as improving electrochemical performance, processing adaptability and production efficiency. The implementation of this step provides a strong guarantee for the high-quality production and wide application of composite copper foil.

[0063] Example 1

[0064] A production process of a multifunctional composite copper foil comprises the following steps:

[0065] S1. Use a forced air drying oven to bake a 6 μm thick PP carrier layer at 50°C for 16 hours to evaporate the water vapor and oil vapor on the surface of the carrier layer as much as possible.

[0066] S2. Use plasma technology to treat the film surface. The mixing ratio of argon and oxygen is 98:2. Plasma treatment can increase the roughness of the film surface and improve the bonding strength between the layers.

[0067] S3. Magnetron sputtering coating is used for base coating. The vacuum degree of magnetron sputtering deposition is controlled at 5×10 -4 -4×10 -3 Pa, using planar magnetron sputtering target (6*127*1700mm) and cylindrical magnetron sputtering target (100*80*1700mm) for sputtering coating, using high-purity copper (99.99%) as the sputtering target material. First, a copper coating less than 100nm is coated on the polymer base film, and then high-purity argon is used as the sputtering gas to sputter the copper target. The copper target is bombarded by argon ions, and the sputtered copper atoms are deposited on the surface of the PP carrier layer under the action of the electromagnetic field. Finally, a copper film of about 100nm is deposited on the surface of the PP carrier layer, and the coating speed is 30m / min.

[0068] S4. Evaporation coating: The main purpose of this step is to lay the foundation for subsequent coating, increase conductivity, and facilitate subsequent water electroplating to better control the film thickness. Use high vacuum evaporation coating equipment for pre-coating, use high-purity copper wire (purity is 99.9%) as raw material for high-temperature evaporation coating, the evaporation boat temperature is 1000℃, the coating speed is 30m / min, and the coating thickness is 100nm. After high-temperature evaporation, finally 100nm thick copper is deposited on the film material obtained in step S3.

[0069] S5. Thicken the surface metal layer by water electroplating

[0070] On the basis of the copper layer, the coating is further thickened by copper sulfate electroplating to a total thickness of about 1.0 μm; that is, at 38° C., the film material obtained in step S3 is immersed in a copper sulfate solution for electroplating, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 100 g / L, the mass concentration of copper sulfate is 130 g / L, and the mass concentration of chloride ions is 35 ppm; after the water electroplating is completed, passivation is performed; a passivating agent (citric acid) is used to produce a dense oxide film on the surface of the product to further increase the protection capability, and the operating temperature is 25° C.

[0071] S6. Sample cutting.

[0072] Slitting and rewinding are carried out under a tension of 110-130N.

[0073] Example 2

[0074] A production process of a multifunctional composite copper foil comprises the following steps:

[0075] S1. Use a forced air drying oven to bake a 6 μm thick PP carrier layer at 60°C for 18 hours to evaporate the water vapor and oil vapor on the surface of the carrier layer as much as possible.

[0076] S2. Use plasma technology to treat the film surface. The mixing ratio of argon and oxygen is 98:2. Plasma treatment can increase the roughness of the film surface and improve the bonding strength between the layers.

[0077] S3. Magnetron sputtering coating is used for base coating. The vacuum degree of magnetron sputtering deposition is controlled at 5×10 -4 -4×10 -3 Pa, using planar magnetron sputtering target (6*127*1700mm) and cylindrical magnetron sputtering target (100*80*1700mm) for sputtering coating, using high-purity copper (99.99%) as the sputtering target material. First, a copper coating less than 100nm is coated on the polymer base film, and then high-purity argon is used as the sputtering gas to sputter the copper target. The copper target is bombarded by argon ions, and the sputtered copper atoms are deposited on the surface of the PP carrier layer under the action of the electromagnetic field. Finally, a copper film of about 100nm is deposited on the surface of the PP carrier layer, and the coating speed is 30m / min.

[0078] S4. Evaporation coating: The main purpose of this step is to lay the foundation for subsequent coating, increase conductivity, and facilitate subsequent water electroplating to better control the film thickness. Use high vacuum evaporation coating equipment for pre-coating, use high-purity copper wire (purity is 99.9%) as raw material for high-temperature evaporation coating, the evaporation boat temperature is 1050℃, the coating speed is 30m / min, and the coating thickness is 100nm. After high-temperature evaporation, finally 100nm thick copper is deposited on the film material obtained in step S3.

[0079] S5. Thicken the surface metal layer by water electroplating

[0080] On the basis of the copper layer, the coating is further thickened by copper sulfate electroplating to a total thickness of about 1.0 μm; that is, at 45°C, the film material obtained in step S4 is immersed in a copper sulfate solution for electroplating, the mass concentration of sulfuric acid in the copper sulfate solution is 120 g / L, the mass concentration of copper sulfate is 140 g / L, and the mass concentration of chloride ions is 50 ppm; after the water electroplating is completed, passivation is performed; a passivating agent (citric acid) is used to produce a dense oxide film on the surface of the product to further increase the protection ability, and the operating temperature is 30°C.

[0081] S6. Sample cutting.

[0082] Slitting and rewinding are carried out under a tension of 110-130N.

[0083] Example 3

[0084] A production process of a multifunctional composite copper foil comprises the following steps:

[0085] S1. Use a forced air drying oven to bake a 6 μm thick PP carrier layer at 40°C for 12 hours to evaporate the water vapor and oil vapor on the surface of the carrier layer as much as possible.

[0086] S2. Use plasma technology to treat the film surface. The mixing ratio of argon and oxygen is 98:2. Plasma treatment can increase the roughness of the film surface and improve the bonding strength between the layers.

[0087] S3. Magnetron sputtering coating, the vacuum degree of magnetron sputtering deposition is 5×10 -4 -4×10 -3 Pa, using planar magnetron sputtering target (6*127*1700mm) and cylindrical magnetron sputtering target (100*80*1700mm) for sputtering coating, using high-purity copper (99.99%) as the sputtering target material. First, a copper coating less than 100nm is coated on the polymer base film, and then high-purity argon is used as the sputtering gas to sputter the copper target. The copper target is bombarded by argon ions, and the sputtered copper atoms are deposited on the surface of the PP carrier layer under the action of the electromagnetic field. Finally, a copper film of about 100nm is deposited on the surface of the PP carrier layer, and the coating speed is 30m / min.

[0088] S4. Evaporation coating: The main purpose of this step is to prepare the base for subsequent coating, increase conductivity, and facilitate subsequent water electroplating to better control the film thickness. Use high vacuum evaporation coating equipment for pre-coating, use high-purity copper wire (purity of 99.9%) as raw material for high-temperature evaporation coating, the evaporation boat temperature is 950℃, the coating speed is 30m / min, and the coating thickness is 100nm. After high-temperature evaporation, finally 100nm thick copper is deposited on the film material obtained in step S2.

[0089] S5. Thicken the surface metal layer by water electroplating

[0090] On the basis of the copper layer, the coating is further thickened by copper sulfate electroplating to a total thickness of about 1.0 μm; that is, at 30° C., the film material obtained in step S3 is immersed in a copper sulfate solution for electroplating, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 80 g / L, the mass concentration of copper sulfate is 120 g / L, and the mass concentration of chloride ions is 20 ppm; after the water electroplating is completed, passivation is performed; a passivating agent (citric acid) is used to produce a dense oxide film on the surface of the product to further increase the protection capability, and the operating temperature is 20° C.

[0091] S6. Sample cutting.

[0092] Slitting and rewinding are carried out under a tension of 110-130N.

[0093] Comparative Example 1

[0094] A production process of a multifunctional composite copper foil comprises the following steps:

[0095] S1. Use a forced air drying oven to bake a 6 μm thick PP carrier layer at 50°C for 16 hours to evaporate the water vapor and oil vapor on the surface of the carrier layer as much as possible.

[0096] S2. Use plasma technology to treat the film surface. The mixing ratio of argon and oxygen is 98:2. Plasma treatment can increase the roughness of the film surface and improve the bonding strength between the layers.

[0097] S3. Magnetron sputtering coating

[0098] High vacuum evaporation coating equipment is used for pre-coating, and high-purity copper wire (purity is 99.9%) is used as the raw material for high-temperature evaporation coating. The evaporation boat temperature is 1050°C, the coating speed is 30m / min, and the coating thickness is 100nm. After high-temperature evaporation, 100nm thick copper is finally deposited on the basis of the film material in step S1.

[0099] S4. Thicken the surface metal layer by water electroplating

[0100] On the basis of the copper layer, the coating is further thickened by copper sulfate electroplating to a total thickness of about 1.0 μm; that is, at 45° C., the film material obtained in step S2 is immersed in a copper sulfate solution for electroplating, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 120 g / L, the mass concentration of copper sulfate is 140 g / L, and the mass concentration of chloride ions is 50 ppm; after the water electroplating is completed, passivation is performed; a passivating agent (citric acid) is used to produce a dense oxide film on the surface of the product to further increase the protection capability, and the operating temperature is 30° C.

[0101] S5. Sample cutting

[0102] Slitting and rewinding are carried out under a tension of 110-130N.

[0103] Comparative Example 2

[0104] A production process of a multifunctional composite copper foil comprises the following steps:

[0105] S1. Use a forced air drying oven to bake a 6 μm thick PP carrier layer at 50°C for 16 hours to evaporate the water vapor and oil vapor on the surface of the carrier layer as much as possible.

[0106] S2. Use plasma technology to treat the film surface. The mixing ratio of argon and oxygen is 98:2. Plasma treatment can increase the roughness of the film surface and improve the bonding strength between the layers.

[0107] S3. Evaporation coating: The main purpose of this step is to prepare the base for subsequent coating, increase conductivity, and facilitate subsequent water electroplating to better control the film thickness. Use high vacuum evaporation coating equipment for pre-coating, use high-purity copper wire (purity of 99.9%) as raw material for high-temperature evaporation coating, the evaporation boat temperature is 950℃~1050℃, the coating speed is 30m / min, the coating thickness is 100nm, and after high-temperature evaporation, finally deposit 100nm thick copper on the basis of the film material obtained in step S2.

[0108] S4. On the basis of the copper layer, the coating is further thickened by copper sulfate electroplating to a total thickness of about 1.0 μm; that is, at 45°C, the film material obtained in step S2 is immersed in a copper sulfate solution for electroplating, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 120 g / L, the mass concentration of copper sulfate is 140 g / L, and the mass concentration of chloride ions is 50 ppm; after the water electroplating is completed, passivation is performed; a passivating agent (citric acid) is used to produce a dense oxide film on the surface of the product to further increase the protection capability, and the operating temperature is 30°C.

[0109] S5. Sample cutting.

[0110] Slitting and rewinding are carried out under a tension of 110-130N.

[0111] 1. Examples 1-3 and Comparative Examples 1-2 were subjected to the following performance tests:

[0112] For the performance tests of tensile strength, elongation and surface roughness, please refer to the national standard GB / T 5230-2020 "Electrolytic copper foil for printed circuit boards". The test results are shown in Table 1 below.

[0113] The surface square resistance performance test refers to the national standard GB / T 17473.3-2008 "Test method for precious metal paste for microelectronics technology - Determination of square resistance", and the test results are shown in Table 1 below.

[0114] For the surface tension performance test, please refer to the national standard GB / T 22638.4-2016 "Aluminum foil test method Part 4: Determination of surface wetting tension". The test results are shown in Table 1 below.

[0115] The adhesion performance test refers to the national standard GB / T 2792-2014 "Test method for peel strength of adhesive tape", and the test results are shown in Table 1 below.

[0116] Table 1

[0117] Test indicators Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tensile strength MPa 217 210 204 196 188 Elongation % 20.3 19.9 18.9 18.4 16.8 Surface resistance mΩ / □ 17.5 18.2 18.8 19.6 19.4 Surface roughness μm 0.33 0.31 0.30 0.29 0.27 Surface tension mN / m 42 40 40 40 40 Adhesion N / 15mm 2.8 2.5 2.1 2.0 1.9

[0118] 2. Apply the composite copper foils of Examples 1-3 and Comparative Examples 1-2 to the battery field, and then perform corresponding battery performance tests;

[0119] Battery Assembly:

[0120] Positive electrode: lithium iron phosphate;

[0121] Negative electrode sheet: composed of the composite copper foil prepared as above and a graphite active layer coated on the composite copper foil;

[0122] Electrolyte: liquid electrolyte with lithium hexafluorophosphate as solute;

[0123] Diaphragm: Polyethylene (PE) microporous diaphragm;

[0124] The prepared positive electrode sheet, negative electrode sheet and separator are wound into an electrode group, and then the lithium-ion battery is made by copper-plastic packaging, liquid injection, standing, pressurization and degassing.

[0125] Performance testing: The performance of the carrier film was tested using a lithium-ion battery test system in accordance with the standard GB / T 31484-2015 "Requirements and test methods for cycle life of power batteries for electric vehicles". The specific test conditions include: 1000 cycles at 25°C, 1C charge and discharge rate, 100% discharge depth and 2 atmospheres. After testing the lithium-ion battery test system, the discharge capacity was ≥ 90% of the initial capacity after 1000 cycles at 25°C, 1C charge and discharge rate, 100% discharge depth and 2 atmospheres; the test results are summarized in Table 2 below.

[0126] Table 2

[0127] Test indicators Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Internal resistance mΩ 18 19 20 25 22 Capacity retention rate % 91 91 90 85 89

[0128] The raw materials or reagents used in the embodiments of the present invention and the comparative examples are all purchased from mainstream manufacturers in the market. Those without indicating the manufacturer or the concentration are all analytically pure raw materials or reagents that can be routinely obtained, as long as they can play the expected role, there is no particular restriction. The instruments and equipment such as the reactor and rotary evaporator used in the present embodiment are all purchased from major manufacturers in the market, as long as they can play the expected role, there is no particular restriction. If specific techniques or conditions are not indicated in the present embodiment, the techniques or conditions described in the literature in this area or according to the product specification are carried out.

[0129] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A production process of a multifunctional composite copper foil, characterized in that: The following steps are involved: S1. Baking the carrier layer; S2. Surface treatment by plasma treatment; S3. coating a bottom layer on the baked carrier layer by magnetron sputtering; S4. Vacuum evaporation is performed on the bottom layer to form a vacuum-deposited layer; S5. Plating a copper layer on the vacuum evaporated layer by water electroplating; S6. Sample cutting.

2. The production process according to claim 1, characterized in that: In step S1, the baking temperature is 40-60°C and the baking time is 12-18 hours.

3. The production process according to claim 1, characterized in that: In step S3, the vacuum degree of magnetron sputtering deposition is 5×10 -4 -1×10 -3 Pa, planar magnetron sputtering target and cylindrical magnetron sputtering target are used for sputtering coating, and copper is used as the sputtering target material.

4. The production process according to claim 3, characterized in that: In step S3, a copper coating less than 100 nm is coated on the carrier layer, and a copper target is sputtered using high-purity argon as a sputtering gas. The copper target is bombarded by argon ions, and the sputtered copper atoms are deposited on the surface of the carrier layer under the action of an electromagnetic field. Finally, a copper film is deposited on the surface of the carrier layer to form a base layer.

5. The production process according to claim 1, characterized in that: In step S1 , the material of the carrier layer includes but is not limited to: any one or more of PET (polyethylene terephthalate), PP (polypropylene), and PI (polyimide).

6. The production process according to claim 1, characterized in that: In step S4, the vacuum evaporation temperature is 950° C. to 1050° C., the coating speed is 30 m / min, and the coating thickness is 100 nm.

7. The production process according to claim 1, characterized in that: In step S5, the water electroplating is to immerse the film material obtained in step S4 in a copper sulfate solution for electroplating at 30-45°C, wherein the mass concentration of sulfuric acid in the copper sulfate solution is 80-120 g / L, the mass concentration of copper sulfate is 120-140 g / L, and the mass concentration of chloride ions is 20-50 ppm.

8. The production process according to claim 7, characterized in that: In step S5, after the water electroplating is completed, passivation is performed; the operating temperature of the passivation is 20-30°C.

9. A multifunctional composite copper foil, characterized in that: The composite copper foil is a composite copper foil prepared by the production process of any one of claims 1 to 8.

10. An application of a multifunctional composite copper foil, characterized in that: The multifunctional composite copper foil according to claim 9 is applied to prepare batteries.

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